It is necessary for transmitters used in certain applications to transmit signals, or messages, having a relatively small information content, referred to herein as little depth of information. For example, the transmission of a metered value could be a message of little information depth. Also, a transmission of a simple on/off signal combined with an identification number or code could have only a little depth of information. To fulfill their task, transmitters of the generic type such as, e.g. wireless sensors, must manage with a limited power reserve available to them. When such a transmitter is operated, the required power is divided into a portion of useful power which flows into the transmitted signal and a portion of dissipated power which, ultimately converted into e.g. heat energy which is not needed, is lost.
Printed document DE 19947344 A shows a sensor with transmitting and receiving unit for wireless data transmission with low power consumption, the low power consumption in the device according to printed document DE 19947344 A being given by the fact that in idle mode, when no signal is being transmitted, a sleep mode with low power consumption is engaged. The sleep mode is ended by means of a cyclically repeating modulated synchronization signal of a base station, which is received by the device, and the device transmits modulated data signals to the base station. After the transmission of the modulated data signals, the device drops back into the sleep mode. During this sleep mode, the power consumption of the device is low since the power-consuming transmitting operation of the device is limited to the period at which the base station is requesting data. Should the data transmission be faulty due to an interference signal and the data would otherwise be lost, the data signal is transmitted repetitively in a recurring mode. This occurs at identical time intervals until the device receives a modulated acknowledgement signal which is transmitted by the base station to the device after having successfully received the data. This means, on the one hand, the device is operating a bidirectional radio traffic with the base station and, on the other hand, the device is transmitting independently of the interference frequencies of adjacent interfering transmitters until the data are received error-free by the base station. The transmitting of the data signal is thus actually not power-optimized. Power optimization is only related to the period during which the sleep mode is active.